Thumbs, Toes, and Tears Read online

  Greenfield’s research has led her to theorize that the advances children make in her experiments parallel the mental evolution of our predecessors. But what puzzles would our ancestors have been trying to solve two million years ago, and how would they have shaped the brain we have today?

  …

  Because we have only two hands, rather than, say, eight tentacles, like an octopus, we manipulate objects in an ordered sequence, not all at once. That means to consciously do “A” before “B” and “B” before “C,” we have to focus. You don’t absentmindedly build a bow, or shape an arrow, or design a steam engine. It requires intention and concentration. Anyone who has struggled with assembling furniture at home knows that if B does not follow after A and C upon B, things have a way of falling apart.

  If scientists such as Lakoff, Johnson, and Greenfield are right, we manipulate thoughts the way we do because our hands once learned to shape sticks, stones, and animal skins into tools. Nouns became the equivalents of objects, verbs represented actions, and we (or our hands) took on the role of a sentence’s subject.

  To ancestors like Handy Man, the physical grammar of cracking open a femur to eat the marrow inside might have gone something like, “Hit bone (with) stone.” He might not have had any words—any mental symbols—to attach to these objects or actions, but the pattern of using one thing to affect another would have been part of his physical experience. There was no way around it. If you pick up a stone to strike a bone, certain actions must unfold in a certain sequence for the whole business to work out. The brain must consciously conceive and act on that sequence, or the bone and stone will forever sit there, and never the twain shall meet. And any ape that spends his day gazing at a rock and bone, doing nothing, will never eat an ounce of marrow, and certainly won’t live long enough to pass his genes along. Animals like these, as scientists like to say, “get selected out.”

  The unavoidable conclusion here is that toolmaking not only resulted in tools, but also in the reconfiguration of our brains so they comprehended the world on the same terms as our toolmaking hands interacted with it. The physical conversation our marionette fingers were having with the objects around us was shaping the way our brain organized and thought about everything. The hand speaks to the brain as surely as the brain speaks to the hand.11 Art, or at least craft, was beginning to imitate life, and the rudiments of language and complex human thought were sprouting from the sense-able, concrete sequences of that life.

  …

  In 1996, Vittorio Gallese, Giacomo Rizzolatti, and their colleagues at the University of Parma in Italy inadvertently discovered the strange and mysterious ways in which evolution works. They were recording signals transmitted from neurons in an area of the brains of macaque monkeys called the F5 region. This is a specific sector of the frontal lobes that sits among a larger area of the brain that deals with making and anticipating movements called, fittingly, the premotor cortex.12

  The scientific team already knew that F5 neurons fired when monkeys performed specific goal-oriented tasks with their hands or mouths—picking up a peanut and then holding it, for example. But for this series of tests they wanted to see if the F5 neurons acted any differently when the objects themselves were different. Did it matter, they wondered, if a monkey was picking up a peanut rather than a slice of apple?

  It was while they were performing this routine experiment that they noticed something odd. When a macaque watched a researcher’s hand pick up an object and bring it close to his mouth, the sensors connected to the monkey’s brain indicated that neurons in its F5 region were firing. They didn’t activate when the monkeys simply saw the objects sitting there, only—and this was what was so unusual—when the monkey watched researchers pick them up, or when the monkeys themselves picked them up.

  The implications of this are enormous. If the same neurons were firing in the monkeys’ brains when they watched the action, it meant they were playing out what they were seeing before them inside their own brain—their mind’s eye—just as if they were doing it themselves. They were mentally “mirroring” the physical action. You could also say that in a rudimentary way they were imagining they were doing the action; reliving, neuron by firing neuron, the experiences of others—in effect, putting themselves in the shoes of the researchers they were watching. They were experiencing a form of empathy that itself required a kind of imagination.

  The ignition of F5 neurons made these seemingly simple gestures and maneuvers a form of communication far more powerful than any hoot, grunt, or howl. After all, if the monkey was mentally picturing the actions of the researcher, it was also quite possibly remembering and learning it. Monkey see, monkey do.

  If you look hard, you can catch glimpses of early conscious communication on all sides of this. Imagine two habiline creatures—a parent and a child—sitting in their small, lakeside camp two million years ago, smoke billowing from the enormous volcanoes at their backs. They have roughly twice the neuronal wetware of the average chimp today (and certainly more than a macaque monkey), so their intelligence is far from trivial. On the other hand, they still can’t speak, so their ability to share what is on their minds is limited, even though they undoubtedly have far more to communicate than any of the other animals around them.

  Now imagine the parent is making a simple tool, like those that Nicholas Toth and his colleagues experimented with. The child watches intently. Simply by observing, the same neurons—her mirror neurons—are firing in her head that are firing in her parent’s. And so when she attempts to repeat the action she has been watching, she can call upon those fired neurons to guide her hands to do something she has never actually done before but has imagined doing.

  For his part, when the parent strikes flint against the rock, he is silently talking to the watching child. He is saying, with his hands, “This is how you make this thing. You hold this large rock like this and strike it with this small rock just so.” You can see him holding up the sharp sliver of flint that the blow has created. “See, now you have a knife.” And then next, he may carve the skin off a carcass, taking the “conversation” in a new direction.13

  The entire time the child is “listening.” Neither parent nor daughter have any language; not a single word they can exchange, not even a concept of words, only the looks on their faces, the expressions in their eyes, the gestures they make with their hands as they manipulate and exchange the rocks and flint. But a lot of information is traveling back and forth between their two minds. In a very real sense they are conversing.

  This apparent connection between conversation and manipulation is more than metaphorical. More recent research, built on Gallese’s and Rizzolatti’s original discovery, has revealed that the F5 region in macaque monkeys is an analog for areas in our own brain essential for generating human language and speech (not necessarily the same thing, as we shall see). We know this partly because a few years after the discovery of mirror neurons, Rizzolatti and another researcher, Scott Grafton, found that when humans watch someone handle objects, a region of the brain called the superior temporal sulcus, which sits directly behind the left temple, activates and mirrors what they see. This surprised scientists because they had long thought that this part of the brain existed primarily to send the signals to Broca’s area that generate speech. Now it appeared Broca’s area was handling other jobs as well, or deeper ones. It not only sent signals to the muscles that generated speech, it sent the signals to hands and arms that enabled the precise manipulation of objects.14

  Rizzolatti thinks this fusion of objects and imagination, gestures and words provides a glimpse into the genesis of language. Mirror neurons might be the primal wetware that enabled our ancestors to transform the common ground of doing and making into the earliest forms of conscious communication. F5, or something like it, might very well have been the bud from which Broca’s area—a cornerstone of human language—blossomed.

  The Insights of Dr. Broca

  How we actually generate l
anguage is a mystery, but we know that we can’t do it if a part of the brain known as Broca’s area, named for the brilliant French doctor and anatomist Pierre Paul Broca, who discovered it, doesn’t function properly. Broca first located this part of the brain when he performed an autopsy in 1861 on a patient, known as Tan, who had died from gangrene. The man was known as Tan because when he tried to speak all he seemed capable of saying again and again was the word “tan.” This affliction became known as Broca’s aphasia, and the autopsy revealed that there had been damage to specific sections of the inferior frontal gyrus in the left frontal lobe of the brain (roughly near the left temple). Subsequent studies Broca and others performed confirmed that in most people (left-handers usually being the exception) this is the area of the brain that somehow takes the symbols our minds create when we want to communicate, attaches sounds to them, and then coordinates sending the signals to all of the muscles needed to make the precise sounds we call speech (or in the case of those who can’t speak, make the hand signals needed to communicate).

  Brain scanning technology has confirmed Broca’s findings. These areas of the brain “light up” when we generate speech. Broca’s area is connected to Wernicke’s area by a neural pathway called the arcuate fasciculus, and using these two sectors of the brain, we handle most of the generation and understanding of the spoken (or signed) word. Because Broca’s area is so closely located next to areas of the brain associated with mirror neurons and those sectors that control both facial muscles and hand coordination, it may help explain how toolmaking, gestures, and speech are connected.

  With mirror neurons, something entirely new had entered the world: a far more effective and speedy method for pooling knowledge and passing it around than the old genetic way. Ideas could now be shared between minds! And that sort of knowledge-pooling, as Darwin observed, would have seriously improved the chances of a troop’s, a family’s, or an individual’s survival. As he put it, “the plainest self-interest, without the assistance of much reasoning power, would prompt the other members [of a tribe] to imitate him; and all would thus profit.… If the invention were an important one, the tribe would increase in number, spread and supplant other tribes.”15

  This means that two astounding advances were unfolding during Homo habilis’s brief stay on Earth. First, entirely new knowledge was being intentionally generated out of the brain of a single creature. Toolmaking marked the birth of invention. Second, knowledge could now be duplicated and relocated to other minds; it was no longer doomed to die with the brain that conceived it. Just as the evolution of DNA made it possible for a gene to be copied and shared from one generation to the next, mirror neurons, and the new behaviors they made possible, meant that an idea—a “meme,” as Richard Dawkins has put it—could be copied and passed along from one mind to the next.16 Conscious communication had emerged, even if only in an embryonic form, and in its wake everything from gossip to oratory, mathematics to the laws of Hammurabi, stand-up comedy to the computer code that sends probes to the moons of Saturn would follow. We were building the scaffolding for true human behavior, relationships, and, ultimately, that most monumental of all human inventions: culture.

  But how would our ancestors even begin to cross the chasm that yawned between the first flint knives and the great edifices of human endeavor we have erected since?

  Chapter 4

  Homo hallucinator—the Dream Animal

  Man is a singular creature. He has a set of gifts which make him unique among the animals: so that, unlike them, he is not a figure in the landscape—he is a shaper of the landscape.

  —Jacob Bronowski

  We inhabit a language rather than a country.

  —Emile M Cioran

  Colorless green ideas sleep furiously.

  —Noam Chomsky

  Human culture requires massive mind-sharing. Inventions such as money, trade, government, religion, literature, and agriculture are cooperative ventures that demand intricate bridges, trestles, and aqueducts of communication, and for those we need language. It shapes us as much as we shape it.

  Philosophers, linguists, and anthropologists have been debating the origins of language for centuries, and still the arguments tumble on. Some theories date back to the nineteenth century, and today many aren’t taken as seriously as they once were. There is the Bow-Wow or onomatopoeic theory, which holds that speech arose when our ancestors imitated environmental sounds—the oink of a boar or the sounds of the wind. Words such as “crash,” “whoosh,” and “bang,” which sound like the actions they describe, are good examples.

  Then there is the Pooh-Pooh theory, the idea that language arose out of instinctive cries such as “ouch “or “oh” or “yikes!” The Ding-Dong theory suggests that our ancestors reacted to the world around them by spontaneously producing sounds we associated with a person or a thing. Mama, for example, might have evolved out of the “mmmm” sound that goes along with nursing.

  There are other theories. Ethologist and linguist E. H. Sturtevant has wondered if human language developed because humans found a selective advantage in being able to deceive others. Exclamations such as a yelp or a moan can involuntarily reveal your true mental state, so, according to Sturtevant, humans learned to fake them to deceive others for selfish advantage. There may be something to that, but it doesn’t really solve the problems of the mechanics or cerebral wiring needed for speech.1

  Psychologist Peter MacNeilage at the University of Texas at Austin theorizes that Broca’s area evolved in humans as the brain center that produces speech because that part of the brain also handles sucking, biting, and swallowing. Maybe, he argues, these functions helped to frame and separate the sounds we make that eventually became words.

  Darwin at least partly subscribed to the theory that language evolved from the sudden, unconscious noises our ancestors made (the Pooh-Pooh theory). “[Anyone] fully convinced, as I am, that man is descended from some lower animal,” he wrote, “is almost forced to believe a priori that articulate language has developed from inarticulate cries.”

  These theories basically hold that somehow we began to make noises that we came to attach to actions and things in the world around us, and then began to string them together into simple pidgins, or protolanguages. Proponents agree that these strings of sounds may not have worked very well, but they were more effective than body language and limited facial expressions. Whatever the case, from these protolanguages, the theories go, modern language developed.

  But what these models don’t explain is how our ancestors began putting words in an order that wasn’t simply random. Pidgins, for example, pile words together without much regard to their order, which severely reduces their effectiveness. Take linguist Derek Bickerton’s example of this Hawaiian-Japanese-English pidgin construction: “aena tu macha churen, samawl churen, haus mani pei [translation: and too much children, small children, house money pay].”2 You get a sense of the meaning of this sentence from the words in it, and it is better than nothing, but it is a long way from anything as full-blooded and profound as, say, Shakespeare’s “Tomorrow, and tomorrow, and tomorrow creeps in this petty pace from day to day to the last syllable of recorded time. And all our yesterdays have lighted fools the way to dusty death”—two sentences bristling with metaphor, emotion, insight, and organization.

  The order of words in a language is at the heart of its syntax, and syntax is the bedrock of grammar, the organizational rules that define and differentiate the underlying structure of every language. Vocabulary may supply the bricks and the mortar, but without syntax and grammar there would be no such thing as language as we know it—they supply its shape and design, its studs, struts, foundations, and supports. How could all of this come together, and how did a brain that could both create and comprehend it emerge?

  …

  The problem for linguists and anthropologists when they set off to decipher these mysteries is that their resources are limited. No concrete examples of early languages exis
t. There are no ossified grammars or words, and while we have the skulls of our ancestors to inspect, they don’t yield many hints about the convoluted structures of the living brains they once housed. There are clues here and there, but they provide little more than a smoking gun, or sometimes just smoke. But there are some other sources of information that scientists are managing to turn up—among them, the nonverbal ways in which we communicated before true language emerged. These have primeval roots that find their way back to the most basic forms of animal communication.

  Some mammals, when they are threatened or square off to fight, raise the fur on their bodies so they look larger and more menacing. When the hair on the back of your neck rises, or you get goose bumps on your forearms walking by a graveyard, that’s a legacy of the same primordial behavior. You are scared, so your first reaction, without a thought, is to raise the fur on your body so you will look fierce, even though you don’t have any fur left to raise. Birds fan their feathers, plump their plumage, or break into exotic dances and resplendent arias to win the attention of the opposite sex. When a wolf bears its teeth and growls, the message is clear: Get out, or prepare for the worst. And what says more than the wagging tail of a dog?